Starting crank for internal combustion engines



Oct. 11, 1932. c, HEUNER 1,882,594

STARTING CRANK FOR INTERNAL COMBUSTION ENGINES Filed Jan. 3.- 1930 3 Sheets-Sheet 1 Fig.2 g-

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ii Inventor by wo/vzewm v Oct. 11, 1932. v c, HEUNER 1,882,594

STARTING CRANK FOR INTERNAL COMBUSTION ENGINES Filed Jan. 3, 1930 I 3 Sheets-Sheet 2 Fig.4 Fig.5

h 0 m h n I i f d d Inventor w A ftorney Oct. 11, 1932. c. HEUNER 1,382,594

STARTING CRANK FUR INTERNAL COMBUSTION ENGINES Filed Jan. 5, 1930 s Sheets-Sheet 5 Fig.5 81 i lnvenfor A Home y Patented Oct. 11, 1932 UNITED STATES;

CARL HEUNER, OF BERLIN, GERMANY STARTING CRANK FOR INTERNAL comnusrron ENGINES Application filed January 3, 1930, Serial No. 418,271, and in Germany May 25, 1928.

My invention relates to improvements in starting cranks for internal combustion engines, and the object of the improvements is to provide a crank which yields relatively to the shaft of the'engine when the velocity of the said shaft is higher than that of the crank, and when the shaft is rotated backwardly by the pistons of the engine. -With this object in view my invention consists in constructing the crank arm and; the hub of the crank in two parts pivotallyconnected with each other, and providing a coupling member in connection with the hub which is operatively connected with the crank arm for bemg thrown into coupling engagement with the shaft of the engine, and which is automatically thrown out of coupling engagement with the shaft when the velocity of the shaft exceeds that of the crank or when the said shaft rotates in opposite direction. Thus the reaction of the shaft'of the engine on the crank arm is very small so that the attendant is not endangered.

For the purpose of explaining the invention an example embodying the same has been shown in the accompanying drawings in which the same reference characters have been used in all the views to indicate corresponding parts. In said drawings,

Fig. 1 is a sectional elevation showing the crank and a part-of the shaft of the engine,

Fig. 2 is a sectional elevation taken on the line 2-2 of Fig. 1, the crank arm being shown in inoperative position.

Fig. 3 is asimilar sectional elevation showing the crank arm in position for starting the engine,

Fig. 4 is a similar sectional elevation show ing the crank arm in position for starting the engine and the motor shaft in position for uncoupling the crank when runningat a higher velocitythan the crank arm,

Fig. 5 is a similar sectional elevation showing the crank arm in position for starting the engine, and the engine shaft in position for uncoupling the crank when rotating in opposite direction to the crank,

Fig. 6 is a sectional elevation similar to the one illustrated in Fig. 1 and showing a modification of thecrank comprising a rockable coupling member, and

Fig. 7 is a sectional elevation taken on the line 77 of Fig. 6.

In the example shown in'the drawings the crank for driving the engine shaft It consists of a hub made intwo sections a, a ,a crank arm I; jointed theretoby means of'a pivot d and a handle 0. I

The'hub a, a provides a pocket or guideway for a slide 0 providing a couplingmemher for coupling the hub to the shaftlt, and the said slide 6 is formed -with a hole is through which the outer end of the shaft h is passed. The said outer end is formed with a notch 2', providing an eccentric portion 1 which as shown is plane. The hole k is formed with a corresponding eccentric or plane portion m, and its dimension is such that the shaft may rotate therein without engaging the wall of the hole is, as is shown in Fig. 2. The slide e is adapted to be shifted into coupling engagement with the shaft h and with the eccentric faces mand Z bearing on each other, as is shown in Fig. 3, and such shifting movement is imparted to the slide by means of the crank arm I), the said crank arm and slide being provided with interengaging teeth f and g. I i

To the rear side of the hub a ratchet wheel 50 p is secured which is engaged by a pawl q mounted on a pin 1 fixed to the frames of the engine, the said pawl and ratchet 'mechanism checking the hub a when the engine shaft rotates in reverse direction upon engine 3 back-fire and thus insuring rapid disconnection of the hub a and the shaft h.

The operation'of the crank is as follows:

Normally the crank arm b is in the position shown in Fig. 2 in which it is symmetrical to the hub a and the coupling s ide e is disposed so that its eccentric portion m is outside the circumference of the shaft h. For starting the engine the crank arm is turned clockwise and into the position shown {is in Fig. 3. Therebythe meshing teeth fland 9 shift the slide 6 to the right and with its eccentric face m' into engagement with the eccentric face Z of the shaft h, the said faces being firmly pressed on each other by reason me remaining in the same angular position relative to the hub.

After the engine has been started the velocity of the shaft it exceeds thatof the crank,

and now the edge n of the shaft engages the face m of the slide 6 thus shifting the said slide to the left and out of coupling engagement, as is shown in Fig. 4. Theforce exerted by the edge 11. exceeds that of the I crank, and it shifts the slide to the left, so

T the hub a, a

that the shaft h is free to rotate'within'the' hole la. When the edge nthus engages the face m for shifting the slide 6 to the left, a reaction is exertedon the teeth g of the crank arm 6. But thisreaction does not transmit a blow to. the hand of the attendant, because the hub'a and the arm I) which are pivotally connected with eachother are slightly rockedto the left, the-crank arm 5 rocking about the handle 0. Byreason of the great length of the crank arm I) as compared to the leverage of the teeth g the reaction'on the handof the attendant is smalL I If when starting the engine the reversely rotated by the pistons, as is indicated by the arrow shown in Fig. 5, the upper edge o'of theface Z engages the face m, so that the slide a is shifted to the left as before, and the crank is immediately discon nected from the shaft and there is no reaction on the crank arm 6. As soon as the reverse rotation of the shaft h begins the pawl g engages the ratchet teeth p and locks the hubin position. Thus the couplingv members It and e are rapidly thrown out of coupling engagement, and the hand is further protected from injury.

g In Figs. 6 and 7 I have shown a modification of the crank in which in lieu of the slide e a couplingmember e is used which is rockingly mounted on a pivot bolt in secured to The coupling member 6 is formedwith teeth 7 engaging with teeth 9 of the crank arm I). The coupling surfaces of the hole of the coupling member and the end of the shaft h are each composed of two faces Z and m disposed at right angles to each other and merging into each other by a roundedportion, the surfacesl being provided by fraising notches 2' on the end of the shaft 7L As appears from Fig. 6, the shaft 7& is in the form of a comparatively short bolt fixed to a hollow shaft 72 by means of a pin 2?. A pawl and ratchet mechanism or a similar locking device may be secured to the hub a or a tubular extension 11 thereof embracing the tubular shaft 72?.

shaft h is Normally the crank is in the position shown in Fig. 7, in which the teeth 7 and g are in loose engagement with each other, and the coupling faces m and Z are out of engagement with each other, permitting the shaft 72, to rotate relativel to the hub and the cou pling member 6 hen the crank arm 6 is rocked to the left for starting the engine the teeth f and g rock the coupling member 6 to the right and with the faces m and Z into coupling engagement. If the engine shaft has begun to rotate the rounded portion connecting the faces Z Z engages the upper face m of the hole 76 thusrocking the coupling member in clockwise direction and out of coupling engagement with the shaft 72. If the shaft 72% is rotated by the pistons of the cylinders in reverse direction with respect to the crank arm the said rounded portion of the shaft 71. engages the lower face m and rocks the coupling member to the'leftl and out of coupling engagement with the shaft.

In the example shown. in the figures the eccentric portions-Z, m and Z m are plane faces. But I wish it to be understood that I do not limit myself to this feature. Further, I do notlimit myself to a construction in which thecrank is mounted on the engine shaft, and that it may be mounted on a part connected with or adapted. to, be connected with the engine shaft, such forexample as'a tubular member 71? provided for connecting the engine with the shaft. In lieu of the couplingslide 6 coupling members in the form of tongs or the like may be provided which are opened by the shaft rotating at a velocity different from that of the crank.

I claim: -1. A crank for starting internal combustion engines, comprising a portion rotatable with the engine shaft, a hub in which said portion is rotatable, a crank arm pivotally mounted on said hub eccentrically of the axis thereof, a coupling member slidable on said hub and adapted for coupling engagement with said portion and normally out of coupling engagement therewith, said portion and member being formed with coupling faces adapted upon rotation of the portion relatively to the hub to shift said member out of coupling position, and means on said crank arm and member operative when rocking the crank arm in a direction for starting theengine for moving said member into coupling engagement with said portion.

2. A crank for starting internal combustion engines,comprising a portion rotatable with the engine shaft, a hub in which said portion is rotatable, a crank arm pivotally mounted on saidhub eccentrica-lly of the axis thereof, a coupling member rockingly mounted on said hub and adapted for coupling engagement with said portion and normally out of coupling engagement therewith, said portion and member being formed with coupling faces adapted upon rotation of the portion relatively to the hub to shift said member out of coupling position, and means on said crank arm and member operative when rocking the crank arm in a direction for starting the engine for rocking said member into coupling engagement with said portion.

3. A crank for starting internal combustion engines, comprising a portion rotatable with the engine shaft, a hub in which said portion is rotatable, a crank arm pivotally mounted on said hub eccentrically of the axis thereof, a coupling member rockingly mounted on said hub and havinga hole embracing the portion connected with said shaft and formed with a wall adapted for coupling engagement with said portion, said coupling member being normally out of coupling engagement with said portion, and said portion and member being formed with coupling faces adapted upon rotation of the portion relatively to the hub to shift said member out of coupling position, and means on said crank arm and member operative when rocking the crank arm in a direction for starting the engine for rocking said member into coupling engagement with said portion.

A. A crank for starting internal combustion engines, comprisin a portion rotatable with the engine shaft, a hub inwhich said portion is rotatable, a crank arm pivotally mounted on said hub eccentrically of the axis thereof, a coupling member rockingly mounted on said hub and adapted for coupling engagement with said portion and normally out of coupling engagement therewith, the fulcrums of said crank arm and coupling member being located at opposite sides of said portion rotatable with the engine shaft, said portion and member being formed with coupling faces adapted upon rotation of the portion relatively to the hub to shift said member out of coupling position, and means on said crank arm and member operative when rocking the crank arm in a direction for starting the engine for rocking said member into coupling engagement with said portion.

5. A crank for starting internal combustion engines, comprising a portion rotatable with the engine shaft, a hub in which said portion is rotatable, a crank arm pivotally mounted on said hub eccentrically of the axis thereof, a coupling member 'rockingly mounted on said hub and having a hole embracing the portion connected with said shaft and formed with a wall adapted for couplingengagement with said portion, the fulcrums of said crank arm and coupling member being located at opposite sides of said portion rotatable with the engine shaft, said coupling member being normally out of coupling engagement with said portion, and said portion and member being formed with coup-ling faces adapted upon rotation of the portion relatively to the hub to shift said member out of coupling position, and means on said crank arm and member operative when rocking the crank arm in a direction for starting the engine for rocking said member into coupling engagement with said portion.

6. A crank for starting internal combustion engines, comprising a portion rotatable with the engine shaft, a hub in which said portion is rotatable, a crank arm pivotally mounted on said hub eccentrically of the axis thereof and extending from its pivot away from the axis of said portion, and a coupling member on said hub and adapted for coupling engagement with said portion and normally out of coupling engagement therewith, said portion and member being formed with coupling faces adapted upon rotation of the portion relatively to the hub to shift said member out of coupling position, and said crank arm and coupling member being formed between the axis of said portion and the pivot of said crank arm with cooperating shoulders adapted when said crank arm is rocked in a direction for starting the engine to throw said coupling member into coupling engagement with said portion and further adapted in case of backfiring to transmit the reaction of said coupling member on said pivot of the crank arm in the direction of the starting rotation.

In testimony whereof I hereunto aifix my signature.

CARL HEUNER. 

